A side air bag device described in Patent Document 1 includes a large-sized air bag that can restrain an occupant from a shoulder to a lumbar. The air bag is disposed in a door-side side portion of a seatback in a folded state. A lower side of the air bag is fixed to a door-side side frame of a seatback frame, and an upper end of the air bag is held by a clip attached to an upper part of the door-side side frame. The clip is configured to support the air bag from a seat rear side upon receipt of a reaction force from the door-side side frame to a seat front side at the time when the air bag is expanded and unfolded.
Examples of the prior art document related to the present invention include Patent Documents 2 to 3.